With Sen. Marco Rubio (R-Fla.) giving the Republican response to President Obama's State of the Union address, many are asking if he's the answer to his party's electoral woes.

Time magazine even put him on the cover and asked if he's the Republican savior.

But there are three big reasons why it's unlikely the Florida senator is on a fast track to the presidency in 2016.

1. Republicans almost always pick the next guy in line.

Ever since the untested Sen. Barry Goldwater (R-Ariz.) lost in a historic landslide in 1964, the Republican Party has nearly always picked a nominee who has previously run for national office. The one exception is George W. Bush — and he was the son of a former president.

2. Rubio would face a very tough field.

The 2012 Republican primaries included many candidates who had no shot at ever winning the nomination. The 2016 field is likely to be packed with plausible candidates. Seasoned politicians like Chris Christie, Bobby Jindal, Rick Perry, and Paul Ryan are already lined up and mulling possible bids.

3. Rubio is still largely unknown.

The national spotlight usually uncovers something unflattering in a first-time presidential candidate's past. In last year's GOP primary race, we quickly found out that Newt Gingrich had been a lobbyist for Freddie Mac, Rick Perry couldn't debate, and Herman Cain had issues with women who were not his wife.

Harry Enten adds a couple more marks against Rubio — that he's not liked by the GOP establishment and that he's too conservative — and concludes, "Given the hurdles a Rubio candidacy would face, I honestly wouldn't be surprised if he never runs at all.”